Starting backwards, I don't think self defense is going to hold any water here. K may make a stab at it, but there are too many witnessess that will show BC's "bad character" - plus his own actions or lack thereof, that are just indefensible.
I do think that the final emails were the last straw, though, but I'm not sure if they or any one of them on Friday was from Brett, or was the triggering factor. It could have been emails to or from Krista or one of her friends outlining imminent escape plans. Jessica, remember, was pretty quick to assume BC had done something to Nancy, and her friends were aboard that train immediately. As pointed out, the closer to leaving it gets, the more dangerous it is for the woman. The man realizes the woman is not only defying him (the traitorist b*tch), but he has lost his ultimate control over her. Thus, the rage - he can no longer control her, and he cannot control himself. Domestic violence is the result. Or, as Chief Bazemore said, "domestic violence of the worst kind" - death.
On the email interception I cannot see how anyone would believe an "inadvertant" discovery - especially going back to April and continuing through to her death. And given BC's expertise....
When I first saw the separation draft I was stunned. Incredible, but then I figured that BC must be rolling in it. Evidentally Nancy thought so too, and conveyed that to AS. Then I found out what he actually made, and was not that impressed. BC would have been more than livid. IMO, Nancy should have somehow terminated the living arrangement right then to protect herself.
And, at that, I'm off for luncheon with my daughter and granddaughter, to think of happier things.
MOO